Judge Elizabeth Gaynor said Xing met a 16-year-old girl via messaging app Momo and offered her money in exchange for her virginity.

Eventually she agreed to have sex with him for $20,000 and visited his Box Hill apartment in August 2015.

After the pair had intercourse, which the girl said was painful, Xing took naked photos and videos of her before she left the following morning.

The girl contacted Xing asking for her cheque, but Xing refused to pay unless she returned.

She visited again in September, during which he blindfolded and bound her, and filmed while sexually assaulting her.

He gave her $800 as she left.

Xing continued contacting the girl, telling her she had to have sex with him again otherwise he would tell her boyfriend and publish her photos and videos online for her classmates to see.

In January 2016, Xing took a taxi to the girl's house and told her she had to come outside and engage in sex acts with him otherwise he'd knock on her family's front door and place naked pictures of her in her street.

When she refused to continue seeing him, Xing began uploading naked pictures of the girl onto his Momo messenger account.

Judge Gaynor said Xing attempted to kill himself twice after being arrested, and had been diagnosed with a condition called satyriasis, characterised by a seemingly insatiable sex drive and the need to dominate to make himself feel adequate.

She condemned the infliction of pain and the predatory and brutal nature of his offending, having subjected the girl to "appalling degradation".

Xing, whose Australian visa has been cancelled and has spent six months in detention, will be eligible for parole after four and a half years and has been placed on the sex offenders register for life.

Readers seeking support and information about suicide prevention can contact Lifeline on 13 11 14.